1. Field of the Invention
The invention relates to a process for separating high-resolution LED (light-emitting diodes) chip arrangements fabricated monolithically on a semiconductor substrate wafer, which arrangements have on their back side a pervasive metallizing layer and are separated or sawed along prescribed tracks in border regions, so that they can be arrayed in series with other LED chip arrangements.
2. Technical Background
The economical manufacture of integrated X-Y controllable, large-surface LED displays with the highest possible number of image dots is limited for a number of reasons. A limitation that is purely in terms of area is still imposed today by the size of the epitaxied semiconductor substrate wafer. Another difficulty is the dissipation of heat that occurs in the display, which is a product of the path resistances of the semiconductor material and the metal contacts.
A familiar method for eliminating these difficulties is to make large-surface LED displays by forming a hybrid array of several monolithic LED chips. For this purpose, the LED array chips, which are manufactured monolithically on a wafer, are isolated or separated from one another in the desired number or arrangement. However, the separation process can be performed only with a high reject rate wherein the edge LED's are damaged by means of sawing or scribing.
An object of the invention is to eliminate these disadvantages in a process of the kind described in the introduction and to ensure that the LED chip arrangement that is generated on a semiconductor substrate chip and is to be separated from said chip can be properly arrayed in order to obtain a tight image-dot grid through several LED chip arrangements for a high-resolution LED array when several of these arrangements are aligned in series.